“I had zero expectations going out, it’s been massively overwhelming,” he told BBC Radio Lincolnshire.
“I wasn’t expecting to go out and win.”
Mr Sweeting explained that natural bodybuilding adheres to Olympic rules on drug use, meaning substances such as steroids and weight loss medication are prohibited.
“As a natural you have that nicer sort of shape as you don’t get blown out of proportion compared with the assisted side of the sport,” he added.
Mr Sweeting earned his trip to the United States after winning his category in the UK Natural Bodybuilding championship in September.
He said he got into the sport after struggling with his mental health in his early 20s.
“For me it’s a self-discipline thing,” he said.
“It’s really the journey rather than the destination.”
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